Abstract : Electronic cash (e-cash) permits secure e-payments by providing security and anonymity similar to real cash. Several protocols have been proposed to meet security and anonymity properties of e-cash. However , there are no general formal definitions that allow the automatic verification of e-cash protocols. In this paper, we propose a formal framework to define and verify security properties of e-cash protocols. To this end, we model e-cash protocols in the applied π-calculus, and we formally define five relevant security properties. Finally, we validate our framework by analyzing, using the automatic tool ProVerif, four e-cash protocols: the online and the offline Chaum protocols, the Digicash protocol, and the protocol by Petersen and Poupard.
